Dual Brake Master Cylinders

[Cymru]

Hi all,

I am looking to upgrade my brake master cylinder.

Looking for a dual master cylinder.

Any recommendations out there on make and model?


Many thanks,

[Sea Ranch]

Size matters. Does your car have (or will it have) dual vacuum boosters, or is it going to run without boost?

My car, when I received it, was running a Girling tandem brake master (out of a Spitfire, I believe, so the reservoir sat at an angle, which was okay, but not ideal), .700" bore, and no boosters. Pedal was hard but heavy; almost impossible to lock the brakes. But would probably be fine if run with boosters. Problem with boosters is that they are expensive to buy and maintain (and they will fail eventually; just a matter of time) and two of them take up an enormous amount of space in the engine bay.

I have switched to a single circuit brake system, 5/8" (.625") master, no booster, all new cunnifer and stainless braid/teflon brake lines, full rebuild on calipers, and retrofitted a Sovy unit as a way to monitor any slow or catastrophic brake fluid failure/loss. Looking forward to assessing this fall as the car comes on the road.

YMMV . . . finding a tandem 5/8" bore brake master that fit and also looked right was impossible for me.

Regards from Surrey, BC . . .

Randy

[mbell]

I looked at this and ended up staying with my single circuit 5/8" setup. See:

lotus-suspension-f42/dual-circuit-master-options-t38002.html

[Sea Ranch]

I just plowed through the 3 pages on that thread, Mark. Thanks for mentioning it. In my own readings on the forum I don't think I saw that thread!

Yeah, the Spitfire tandem master on my LHD car fit okay. It needed banjo fittings. I didn't care for the look of it but it worked fine with the sloped reservoir.

Pic below of my current pedal box with both masters in and plumbed, and the Sovy in. Pedal box top cover off (I like lots of access!)

Randy

[1owner69Elan]

Here is a NOS dual master brake cylinder.

https://www.ebay.com/p/Girling-Brake-Ma ... 5016754706

But, as you can see quite pricey.


As I mentioned before these are rather hard to find.

[Sea Ranch]

Nice. Wonder if rebuild kits are available for it.

Not that this is my thread, but this MC still doesn't work for me because I don't like the pedal effort when the stock bore size is used without the boosters.

[1owner69Elan]

Rebuild kits are readily available. Just not the tandem cylinder itself.

[Gray]

Classicar Automotive were advertising tandem cylinders in the Club Lotus magazine last time I looked. I got my tandem cylinder from them together with adjustable pushrods for brake and clutch.

[Sea Ranch]

Ooooh . . . look what just popped on ebay: a used girling tandem master . . .
https://www.ebay.com/itm/Lotus-Europa-S ... 0282.m3503

$60 is a lot less than $475 (although the new one has an offer option in the listing). Have to add in the cost of a rebuild kit for the used one. Both m/c are in the US.

(Again, in my opinion only suitable for use with two good-condition vacuum boosters. )

Randy

[denicholls2]

Just a word of caution (which may be incorrect) regarding the used M/C. Back in the day, there was a lot of discussion regarding how the reservoir could be damaged by removal as seen here. Hopefully not the case.

As the S2 Europa didn't have boosters, this would likely be the right (smaller) bore for an unboosted system.

The other factor is which side the pipes come out. On the Europa, left and right drive are different. And back in the day, there were plenty of right drives available but left-drivers used a Hitachi replacement. ("The day" was about 10 years ago.)

[1owner69Elan]

The Ebay used M/C appears to have the right orientation for a LHD Elan.

The pictures only show a partial disassembly. Refer to this thread on how to fully dismantle and rebuild the tandem M/C:

lotus-suspension-f42/elan-federal-brake-master-cylinder-t36306.html?hilit=Master#p248875

[The Veg]

I think, IIRC, RD has replacements reservoirs but they are expensive and do not include the cap for some strange reason.